Process of making n-dihydro-l



Patented July 5, 1927..

- UNITED STATES PATENT OFFICE.

LYNNE H. 'ULICH, OF RACINE, AND ROBERT J. GOODRICH, OF SOUTH MILWAUKEE,

WISCONSIN, ASS-IGNORS TO THE NEWPORT COMPANY, OF MILWAUKEE, WISCON- SIN, A CORPORATION" OF DELAWARE.

PROCESS OF MAKING N-IDIHYDRO-l-2-2'-1'-ANTHKAQUINONEAZ1NE.

Io Drawing.

This invention relates to coloring matters or intermediates of the anthracene series and a process of making the same, more particularly to'a process of making N-dihydro O 1 :2 2" :1'-anthraquinone azine, known as indanthrene, or its homologsor derivatives.

Heretofore, indanthrene has generally been made by the alkal'r'fusion oi 2-aminoanthraquinonein the 1 ing agent. The products of the reaction are greatly influenced by the temperature at "which the fusion is carried out. Fusions below 250 C., or if in'the absence of an oxidizing agent, yield appreciable uantities 31f: if alizarine, which is very undesira le. Be-

tween 250? and 290 C., the alizarine formed is largely converted into" benzoic acid, pyrocatechuic acid and other soluble acids. Above 290 (1., particularly between 800 and 350 0., some fiavanthrene is formed. And at all of the above-mentioned temperatures, considerable decomposition of the 2-aminoanthraquinone takes place with the formation of, anthraquinone and ammonia and other decomposition products. To purify the crude indanthrene obtained from such a fusion, it is necessary to dissolve it in alkaline hydrosulfite at a certain temperature and then cool it'to a point where the leuco body of indanthrene crystallizes out and maybe filtered ofi', leaving the impurities in the mother liquor.

The present invention has for its object a simple method for obtaining a high yield of indanthrene, its homologs oderivatives,

in a relatively high degree of urity and in such condition that it may be used directly for dyeing from the hydrosulfite vat.

/ Other and further important objects of this invention will be apparentlfrom the disclosures in the followin description,

which sets/forth the preferre form of our- I ter of the anthracene series, which consists 95 invention.

Our invention is essentially one of dehalogenization and consists in heating the halogen derivatives of N-dihydro 1; 2 :2 1,

' anthraquinone azine and homolo s and derivatives thereof with alcoholic potash, with or without the presence of a dissolving or diluting agent 'and with or without a catalyzer. mag ho used in place of alcoholic potash presence of an oxidiz this invention, and we Various dehalogenating agents- Application filed April 4, 1925. Serial No. 20,618.

and also various halogenated derivatives of N-dihydro 1 :2: 2 1-anthraquinone azine. But we prefer to carry out the reaction with dibrom N-dihydro 1: 2 :2 1-anthraquinone az'ine. This may be-- obtained by the condensation of 1:3- dibrom 2-aminoanthrauinone or by any other suitable method. As to number of side reactions occuring durin the dehalogenization process are very few, a high yield of the product is obtained. And further the indanthrene is obtained directly in a relatively hi h degree of purity and may be used direct y for dyeing from the hydrosulfite vat. 4

The followin example will serve to further illustrate t e prbcedure, but the inven tion is not limited to this example, as any halogenated N-dih'ydro 1:2:2:1-anthraquinone azine body and any suitable dehalogenizing agent may be used:

1 Example Add 100 parts by weight of. dibrom N-dihydro- 1 2 :2 r,:'l-anthra,quinone azlne to a previously repared solution of 7 200'parts by weight 0? caustic potash and 400 parts by weight of denatured alcohol. Reflux gently for one hour and then gradually distill-oil? the alcohol, the temperature the process may be varied through a wide from the spirit of erefore do not purpose limiting the patent granted, otherwise than as necessitated by the prior art.

We claim as our invention: v

1. The procew at producing a coloring matrange without dep arting1 in heating dibrom yN-dihydro 1:2:2:1'- anthraquinone azine4 with alcoholic potash to fprm N-dihydro 1:2:2':1' anthraquinone azine. I f 2. The process of producing a coloring! matter of the anthracene series, which consists 'inheating a halogenated N-dihydro 1:2:-2:1'-anthraquinone azine bod 'with a dehalogenizing agent to term a N dihydro 1:2:2':1'-anthraquinone azine body by'the hol ic potash to form N-dihydro L:2:2:1- replacement of the halogen atoms by hydroanthraquinone azine. gen atoms. In testimonx whereof, we have hereunto 10 3. The process of producing aecoloring subscribed ournames.

5 matter of the anthracene series, which consist 'n' heating a. halogenated N-dihydro- LYNNE H. ULICH. 4

1:2:fzY-anthraquinone azine with alco- ROBERT J. GOODRICH. 

